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Duffy SS, Perera CJ, Makker PGS, Lees JG, Carrive P, Moalem-Taylor G. Peripheral and Central Neuroinflammatory Changes and Pain Behaviors in an Animal Model of Multiple Sclerosis. Front Immunol 2016; 7:369. [PMID: 27713744 PMCID: PMC5031691 DOI: 10.3389/fimmu.2016.00369] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/06/2016] [Indexed: 01/27/2023] Open
Abstract
Pain is a widespread and debilitating symptom of multiple sclerosis (MS), a chronic inflammatory demyelinating disease of the central nervous system. Although central neuroinflammation and demyelination have been implicated in MS-related pain, the contribution of peripheral and central mechanisms during different phases of the disease remains unclear. In this study, we used the animal model experimental autoimmune encephalomyelitis (EAE) to examine both stimulus-evoked and spontaneous pain behaviors, and neuroinflammatory changes, over the course of chronic disease. We found that mechanical allodynia of the hind paw preceded the onset of clinical EAE but was unmeasurable at clinical peak. This mechanical hypersensitivity coincided with increased microglial activation confined to the dorsal horn of the spinal cord. The development of facial mechanical allodynia also emerged in preclinical EAE, persisted at the clinical peak, and corresponded with pathology of the peripheral trigeminal afferent pathway. This included T cell infiltration, which arose prior to overt central lesion formation and specific damage to myelinated neurons during the clinical peak. Measurement of spontaneous pain using the mouse grimace scale, a facial expression-based coding system, showed increased facial grimacing in mice with EAE during clinical disease. This was associated with multiple peripheral and central neuroinflammatory changes including a decrease in myelinating oligodendrocytes, increased T cell infiltration, and macrophage/microglia and astrocyte activation. Overall, these findings suggest that different pathological mechanisms may underlie stimulus-evoked and spontaneous pain in EAE, and that these behaviors predominate in unique stages of the disease.
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Affiliation(s)
- Samuel S Duffy
- School of Medical Sciences, UNSW Medicine, The University of New South Wales (UNSW Australia) , Sydney, NSW , Australia
| | - Chamini J Perera
- School of Medical Sciences, UNSW Medicine, The University of New South Wales (UNSW Australia) , Sydney, NSW , Australia
| | - Preet G S Makker
- School of Medical Sciences, UNSW Medicine, The University of New South Wales (UNSW Australia) , Sydney, NSW , Australia
| | - Justin G Lees
- School of Medical Sciences, UNSW Medicine, The University of New South Wales (UNSW Australia) , Sydney, NSW , Australia
| | - Pascal Carrive
- School of Medical Sciences, UNSW Medicine, The University of New South Wales (UNSW Australia) , Sydney, NSW , Australia
| | - Gila Moalem-Taylor
- School of Medical Sciences, UNSW Medicine, The University of New South Wales (UNSW Australia) , Sydney, NSW , Australia
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152
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Infiltrating monocytes promote brain inflammation and exacerbate neuronal damage after status epilepticus. Proc Natl Acad Sci U S A 2016; 113:E5665-74. [PMID: 27601660 DOI: 10.1073/pnas.1604263113] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The generalized seizures of status epilepticus (SE) trigger a series of molecular and cellular events that produce cognitive deficits and can culminate in the development of epilepsy. Known early events include opening of the blood-brain barrier (BBB) and astrocytosis accompanied by activation of brain microglia. Whereas circulating monocytes do not infiltrate the healthy CNS, monocytes can enter the brain in response to injury and contribute to the immune response. We examined the cellular components of innate immune inflammation in the days following SE by discriminating microglia vs. brain-infiltrating monocytes. Chemokine receptor 2 (CCR2(+)) monocytes invade the hippocampus between 1 and 3 d after SE. In contrast, only an occasional CD3(+) T lymphocyte was encountered 3 d after SE. The initial cellular sources of the chemokine CCL2, a ligand for CCR2, included perivascular macrophages and microglia. The induction of the proinflammatory cytokine IL-1β was greater in FACS-isolated microglia than in brain-invading monocytes. However, Ccr2 knockout mice displayed greatly reduced monocyte recruitment into brain and reduced levels of the proinflammatory cytokine IL-1β in hippocampus after SE, which was explained by higher expression of the cytokine in circulating and brain monocytes in wild-type mice. Importantly, preventing monocyte recruitment accelerated weight regain, reduced BBB degradation, and attenuated neuronal damage. Our findings identify brain-infiltrating monocytes as a myeloid-cell subclass that contributes to neuroinflammation and morbidity after SE. Inhibiting brain invasion of CCR2(+) monocytes could represent a viable method for alleviating the deleterious consequences of SE.
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153
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Lehmann ML, Cooper HA, Maric D, Herkenham M. Social defeat induces depressive-like states and microglial activation without involvement of peripheral macrophages. J Neuroinflammation 2016; 13:224. [PMID: 27581371 PMCID: PMC5007852 DOI: 10.1186/s12974-016-0672-x] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/17/2016] [Indexed: 01/27/2023] Open
Abstract
Background We are interested in the causal interactions between psychological stress and activity within different compartments of the immune system. Psychosocial stress has been reported to not only alter microglia morphology but also produce anxiety-like and depressive-like effects by triggering CNS infiltration of macrophages from the periphery. We sought to test these phenomena in a somewhat different but standardized model of chronic social defeat (SD) stress. Methods We used a paradigm of dyadic home pairing of dominant and subordinate mice that has been validated to induce powerful anxiety-like and depressive-like effects manifested by behavior assessed in social tasks. We administered the SD stress for 3 days (acute SD) or 14 days (chronic SD) and looked for monocyte entry into the brain by three independent means, including CD45 activation states assessed by flow cytometry and tracking fluorescently tagged peripheral cells from Ccr2wt/rfp and Ubcgfp/gfp reporter mice. We further characterized the effects of SD stress on microglia using quantitative morphometric analysis, ex vivo phagocytosis assays, flow cytometry, and immunochemistry. Results We saw no evidence of stress-induced macrophage entry after acute or chronic defeat stress. In comparison, brain infiltration of peripheral cells did occur after endotoxin administration. Furthermore, mutant mice lacking infiltrating macrophages due to CCR2 knockout developed the same degree of chronic SD-induced depressive behavior as wildtype mice. We therefore focused more closely on the intrinsic immune cells, the microglia. Using Cx3cr1wt/gpf microglial reporter mice, we saw by quantitative methods that microglial morphology was not altered by stress at either time point. However, chronic SD mice had elevated numbers of CD68hi microglia examined by flow cytometry. CD68 is a marker for phagocytic activity. Indeed, these cells ex vivo showed elevated phagocytosis, confirming the increased activation status of chronic SD microglia. Finally, acute SD but not chronic SD increased microglial proliferation, which occurred selectively in telencephalic stress-related brain areas. Conclusions In the SD paradigm, changes in CNS-resident microglia numbers and activation states might represent the main immunological component of the psychosocial stress-induced depressive state.
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Affiliation(s)
- Michael L Lehmann
- Section on Functional Neuroanatomy, Intramural Research Program, National Institute of Mental Health, NIH, Bldg. 35, Rm. 1C911, Bethesda, MD, 20892-3724, USA.
| | - Hannah A Cooper
- Section on Functional Neuroanatomy, Intramural Research Program, National Institute of Mental Health, NIH, Bldg. 35, Rm. 1C911, Bethesda, MD, 20892-3724, USA
| | - Dragan Maric
- NINDS Flow Cytometry Core Facility, NIH, Bethesda, MD, 20892, USA
| | - Miles Herkenham
- Section on Functional Neuroanatomy, Intramural Research Program, National Institute of Mental Health, NIH, Bldg. 35, Rm. 1C911, Bethesda, MD, 20892-3724, USA
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154
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Davies CL, Miron VE. Distinct origins, gene expression and function of microglia and monocyte-derived macrophages in CNS myelin injury and regeneration. Clin Immunol 2016; 189:57-62. [PMID: 27377535 DOI: 10.1016/j.clim.2016.06.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/27/2016] [Accepted: 06/30/2016] [Indexed: 01/07/2023]
Abstract
Central nervous system (CNS) injury incurs a rapid innate immune response, including that from macrophages derived from endogenous microglia and circulating monocytes infiltrating the lesion site. One example of such injury is the demyelination observed in the autoimmune disease multiple sclerosis (MS), where macrophages are implicated in both myelin injury and regeneration. Although initially microglia and monocyte-derived macrophages were considered to have identical origins, gene expression, and function, recent advances have revealed important distinctions in all three categories and have caused a paradigm shift in view of their unique identity and roles. This has important consequences for understanding their individual contribution to neurological function and therapeutic targeting of these populations in diseases like MS. Here, we address the differences between CNS endogenous and exogenously-derived macrophages with a particular focus on myelin damage and regeneration.
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Affiliation(s)
- Claire L Davies
- MRC Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, United Kingdom
| | - Veronique E Miron
- MRC Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, United Kingdom.
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155
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Friend or Foe? Resident Microglia vs Bone Marrow-Derived Microglia and Their Roles in the Retinal Degeneration. Mol Neurobiol 2016; 54:4094-4112. [PMID: 27318678 DOI: 10.1007/s12035-016-9960-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/06/2016] [Indexed: 01/10/2023]
Abstract
Microglia are immune cells in the central nervous system (CNS) that originate from the yolk sac in an embryo. The renewal of the microglia pool in the adult eye consists of two components. In addition to the self-proliferation of resident cells, microglia in the CNS also derive from the bone marrow (BM). BM-derived cells pass through the blood-brain barrier (BBB) or blood-retina barrier (BRB) and differentiate into microglia under specific conditions which involves a complex mechanism. Recent studies have widely investigated the role of resident microglia and BM-derived microglia in the retinal degenerative disease. Both two cell types play dual roles and share many similar functions. However, resident microglia tend to polarize to the M1 phenotype which is pro-inflammatory and neurotoxic, whereas BM-derived microglia mainly polarize to the neuroprotective M2 phenotype in retinal degeneration. The molecular mechanism that underlines the invasion of peripheral cells has led to extensive discussions. In addition to the BBB and BRB disruption, many signaling pathways are involved in this process. Based on these studies, we discuss the roles of these two types of microglia in retinal degeneration disease and the potential clinical application of BM-derived microglia, which may benefit future therapies.
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156
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Zabel MK, Zhao L, Zhang Y, Gonzalez SR, Ma W, Wang X, Fariss RN, Wong WT. Microglial phagocytosis and activation underlying photoreceptor degeneration is regulated by CX3CL1-CX3CR1 signaling in a mouse model of retinitis pigmentosa. Glia 2016; 64:1479-91. [PMID: 27314452 PMCID: PMC4958518 DOI: 10.1002/glia.23016] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 05/20/2016] [Indexed: 12/20/2022]
Abstract
Retinitis pigmentosa (RP), a disease characterized by the progressive degeneration of mutation‐bearing photoreceptors, is a significant cause of incurable blindness in the young worldwide. Recent studies have found that activated retinal microglia contribute to photoreceptor demise via phagocytosis and proinflammatory factor production, however mechanisms regulating these contributions are not well‐defined. In this study, we investigate the role of CX3CR1, a microglia‐specific receptor, in regulating microglia‐mediated degeneration using the well‐established rd10 mouse model of RP. We found that in CX3CR1‐deficient (CX3CR1GFP/GFP) rd10 mice microglial infiltration into the photoreceptor layer was significantly augmented and associated with accelerated photoreceptor apoptosis and atrophy compared with CX3CR1‐sufficient (CX3CR1GFP/+) rd10 littermates. CX3CR1‐deficient microglia demonstrated increased phagocytosis as evidenced by (1) having increased numbers of phagosomes in vivo, (2) an increased rate of phagocytosis of fluorescent beads and photoreceptor cellular debris in vitro, and (3) increased photoreceptor phagocytosis dynamics on live cell imaging in retinal explants, indicating that CX3CR1 signaling in microglia regulates the phagocytic clearance of at‐risk photoreceptors. We also found that CX3CR1 deficiency in retinal microglia was associated with increased expression of inflammatory cytokines and microglial activation markers. Significantly, increasing CX3CL1‐CX3CR1 signaling in the rd10 retina via exogenous intravitreal delivery of recombinant CX3CL1 was effective in (1) decreasing microglial infiltration, phagocytosis and activation, and (2) improving structural and functional features of photoreceptor degeneration. These results indicate that CX3CL1‐CX3CR1 signaling is a molecular mechanism capable of modulating microglial‐mediated degeneration and represents a potential molecular target in therapeutic approaches to RP. GLIA 2016;64:1479–1491
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Affiliation(s)
- Matthew K Zabel
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Lian Zhao
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Yikui Zhang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Shaimar R Gonzalez
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wenxin Ma
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Xu Wang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Robert N Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
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157
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Ritzel RM, Pan SJ, Verma R, Wizeman J, Crapser J, Patel AR, Lieberman R, Mohan R, McCullough LD. Early retinal inflammatory biomarkers in the middle cerebral artery occlusion model of ischemic stroke. Mol Vis 2016; 22:575-88. [PMID: 27293375 PMCID: PMC4893077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 06/02/2016] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The transient middle cerebral artery occlusion (MCAO) model of stroke is one of the most commonly used models to study focal cerebral ischemia. This procedure also results in the simultaneous occlusion of the ophthalmic artery that supplies the retina. Retinal cell death is seen days after reperfusion and leads to functional deficits; however, the mechanism responsible for this injury has not been investigated. Given that the eye may have a unique ocular immune response to an ischemic challenge, this study examined the inflammatory response to retinal ischemia in the MCAO model. METHODS Young male C57B/6 mice were subjected to 90-min transient MCAO and were euthanized at several time points up to 7 days. Transcription of inflammatory cytokines was measured with quantitative real-time PCR, and immune cell activation (e.g., phagocytosis) and migration were assessed with ophthalmoscopy and flow cytometry. RESULTS Observation of the affected eye revealed symptoms consistent with Horner's syndrome. Light ophthalmoscopy confirmed the reduced blood flow of the retinal arteries during occlusion. CX3CR1-GFP reporter mice were then employed to evaluate the extent of the ocular microglia and monocyte activation. A significant increase in green fluorescent protein (GFP)-positive macrophages was seen throughout the ischemic area compared to the sham and contralateral control eyes. RT-PCR revealed enhanced expression of the monocyte chemotactic molecule CCL2 early after reperfusion followed by a delayed increase in the proinflammatory cytokine TNF-α. Further analysis of peripheral leukocyte recruitment by flow cytometry determined that monocytes and neutrophils were the predominant immune cells to infiltrate at 72 h. A transient reduction in retinal microglia numbers was also observed, demonstrating the ischemic sensitivity of these cells. Blood-eye barrier permeability to small and large tracer molecules was increased by 72 h. Retinal microglia exhibited enhanced phagocytic activity following MCAO; however, infiltrating myeloid cells were significantly more efficient at phagocytizing material at all time points. Immune homeostasis in the affected eye was largely restored by 7 days. CONCLUSIONS This work demonstrates that there is a robust inflammatory response in the eye following MCAO, which may contribute to a worsening of retinal injury and visual impairment. These results mirror what has been observed in the brain after MCAO, suggesting a conserved inflammatory signaling response to ischemia in the central nervous system. Imaging of the eye may therefore serve as a useful non-invasive prognostic indicator of brain injury after MCAO. Future studies are needed to determine whether this inflammatory response is a potential target for therapeutic manipulation in retinal ischemia.
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Affiliation(s)
- Rodney M. Ritzel
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - Sarah J. Pan
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - Rajkumar Verma
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - John Wizeman
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - Joshua Crapser
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - Anita R. Patel
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - Richard Lieberman
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - Royce Mohan
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT
| | - Louise D. McCullough
- Neurology Department, University of Texas Health Science Center at Houston, Houston, TX
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158
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Zhao L, Zabel MK, Wang X, Ma W, Shah P, Fariss RN, Qian H, Parkhurst CN, Gan WB, Wong WT. Microglial phagocytosis of living photoreceptors contributes to inherited retinal degeneration. EMBO Mol Med 2016; 7:1179-97. [PMID: 26139610 PMCID: PMC4568951 DOI: 10.15252/emmm.201505298] [Citation(s) in RCA: 298] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Retinitis pigmentosa, caused predominantly by mutations in photoreceptor genes, currently lacks comprehensive treatment. We discover that retinal microglia contribute non-cell autonomously to rod photoreceptor degeneration by primary phagocytosis of living rods. Using rd10 mice, we found that the initiation of rod degeneration is accompanied by early infiltration of microglia, upregulation of phagocytic molecules in microglia, and presentation of “eat-me” signals on mutated rods. On live-cell imaging, infiltrating microglia interact dynamically with photoreceptors via motile processes and engage in rapid phagocytic engulfment of non-apoptotic rods. Microglial contribution to rod demise is evidenced by morphological and functional amelioration of photoreceptor degeneration following genetic ablation of retinal microglia. Molecular inhibition of microglial phagocytosis using the vitronectin receptor antagonist cRGD also improved morphological and functional parameters of degeneration. Our findings highlight primary microglial phagocytosis as a contributing mechanism underlying cell death in retinitis pigmentosa and implicate microglia as a potential cellular target for therapy.
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Affiliation(s)
- Lian Zhao
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Matthew K Zabel
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Xu Wang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Wenxin Ma
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Parth Shah
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Robert N Fariss
- Biological Imaging Core, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Haohua Qian
- Visual Function Core, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Christopher N Parkhurst
- Department of Neuroscience and Physiology, Skirball Institute New York University School of Medicine, New York, NY, USA
| | - Wen-Biao Gan
- Department of Neuroscience and Physiology, Skirball Institute New York University School of Medicine, New York, NY, USA
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
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159
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Tay TL, Savage JC, Hui CW, Bisht K, Tremblay MÈ. Microglia across the lifespan: from origin to function in brain development, plasticity and cognition. J Physiol 2016; 595:1929-1945. [PMID: 27104646 DOI: 10.1113/jp272134] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/15/2016] [Indexed: 12/11/2022] Open
Abstract
Microglia are the only immune cells that permanently reside in the central nervous system (CNS) alongside neurons and other types of glial cells. The past decade has witnessed a revolution in our understanding of their roles during normal physiological conditions. Cutting-edge techniques revealed that these resident immune cells are critical for proper brain development, actively maintain health in the mature brain, and rapidly adapt their function to physiological or pathophysiological needs. In this review, we highlight recent studies on microglial origin (from the embryonic yolk sac) and the factors regulating their differentiation and homeostasis upon brain invasion. Elegant experiments tracking microglia in the CNS allowed studies of their unique roles compared with other types of resident macrophages. Here we review the emerging roles of microglia in brain development, plasticity and cognition, and discuss the implications of the depletion or dysfunction of microglia for our understanding of disease pathogenesis. Immune activation, inflammation and various other conditions resulting in undesirable microglial activity at different stages of life could severely impair learning, memory and other essential cognitive functions. The diversity of microglial phenotypes across the lifespan, between compartments of the CNS, and sexes, as well as their crosstalk with the body and external environment, is also emphasised. Understanding what defines particular microglial phenotypes is of major importance for future development of innovative therapies controlling their effector functions, with consequences for cognition across chronic stress, ageing, neuropsychiatric and neurological diseases.
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Affiliation(s)
- Tuan Leng Tay
- Institute of Neuropathology, University of Freiburg, Germany
| | - Julie C Savage
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
| | - Chin Wai Hui
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
| | - Kanchan Bisht
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
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160
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The role of microglia and macrophages in glioma maintenance and progression. Nat Neurosci 2016; 19:20-7. [PMID: 26713745 DOI: 10.1038/nn.4185] [Citation(s) in RCA: 1085] [Impact Index Per Article: 135.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/23/2015] [Indexed: 11/08/2022]
Abstract
There is a growing recognition that gliomas are complex tumors composed of neoplastic and non-neoplastic cells, which each individually contribute to cancer formation, progression and response to treatment. The majority of the non-neoplastic cells are tumor-associated macrophages (TAMs), either of peripheral origin or representing brain-intrinsic microglia, that create a supportive stroma for neoplastic cell expansion and invasion. TAMs are recruited to the glioma environment, have immune functions, and can release a wide array of growth factors and cytokines in response to those factors produced by cancer cells. In this manner, TAMs facilitate tumor proliferation, survival and migration. Through such iterative interactions, a unique tumor ecosystem is established, which offers new opportunities for therapeutic targeting.
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161
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Kim CC, Nakamura MC, Hsieh CL. Brain trauma elicits non-canonical macrophage activation states. J Neuroinflammation 2016; 13:117. [PMID: 27220367 PMCID: PMC4879757 DOI: 10.1186/s12974-016-0581-z] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/11/2016] [Indexed: 12/12/2022] Open
Abstract
Background Macrophage polarization programs, commonly referred to as “classical” and “alternative” activation, are widely considered as distinct states that are exclusive of one another and are associated with different functions such as inflammation and wound healing, respectively. In a number of disease contexts, such as traumatic brain injury (TBI), macrophage polarization influences the extent of pathogenesis, and efforts are underway to eliminate pathogenic subsets. However, previous studies have not distinguished whether the simultaneous presence of both classical and alternative activation signatures represents the admixture of differentially polarized macrophages or if they have adopted a unique state characterized by components of both classical and alternative activation. Methods We analyzed the gene expression profiles of individual monocyte-derived brain macrophages responding to TBI using single-cell RNA sequencing. RNA flow cytometry was used as another single-cell analysis technique to validate the single-cell RNA sequencing results. Results The analysis of signature polarization genes by single-cell RNA sequencing revealed the presence of diverse activation states, including M(IL4), M(IL10), and M(LPS, IFNγ). However, the expression of a given polarization marker was no more likely than at random to predict simultaneous expression or repression of markers of another polarization program within the same cell, suggesting a lack of exclusivity in macrophage polarization states in vivo in TBI. Also unexpectedly, individual TBI macrophages simultaneously expressed high levels of signature polarization genes across two or three different polarization states and in several distinct and seemingly incompatible combinations. Conclusions Single-cell gene expression profiling demonstrated that monocytic macrophages in TBI are not comprised of distinctly polarized subsets but are uniquely and broadly activated. TBI macrophage activation in vivo is deeply complex, with individual cells concurrently adopting both inflammatory and reparative features with a lack of exclusivity. These data provide physiologically relevant evidence that the early macrophage response to TBI is comprised of novel activation states that are discordant with the current paradigm of macrophage polarization—a key consideration for therapeutic modulation. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0581-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Charles C Kim
- Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, 1001 Potrero Avenue, Building 3, Room 603, Box 1234, San Francisco, CA, 94143-1234, USA.,Current address: Verily, Mountain View, CA, 94043, USA
| | - Mary C Nakamura
- Department of Medicine, Division of Rheumatology, University of California, San Francisco, 4150 Clement St. 111R, San Francisco, CA, 94121, USA.,Research Department, Immunology Section, San Francisco VA Medical Center, 4150 Clement St. 111R, San Francisco, CA, 94121, USA
| | - Christine L Hsieh
- Department of Medicine, Division of Rheumatology, University of California, San Francisco, 4150 Clement St. 111R, San Francisco, CA, 94121, USA. .,Research Department, Immunology Section, San Francisco VA Medical Center, 4150 Clement St. 111R, San Francisco, CA, 94121, USA.
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162
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Bayerl SH, Niesner R, Cseresnyes Z, Radbruch H, Pohlan J, Brandenburg S, Czabanka MA, Vajkoczy P. Time lapse in vivo microscopy reveals distinct dynamics of microglia-tumor environment interactions-a new role for the tumor perivascular space as highway for trafficking microglia. Glia 2016; 64:1210-26. [PMID: 27143298 DOI: 10.1002/glia.22994] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/05/2016] [Accepted: 04/08/2016] [Indexed: 12/12/2022]
Abstract
Microglial cells are critical for glioma growth and progression. However, only little is known about intratumoral microglial behavior and the dynamic interaction with the tumor. Currently the scarce understanding of microglial appearance in malignant gliomas merely originates from histological studies and in vitro investigations. In order to understand the pattern of microglia activity, motility and migration we designed an intravital study in an orthotopic murine glioma model using CX3CR1-eGFP(GFP/wt) mice. We analysed the dynamics of intratumoral microglia accumulation and activity, as well as microglia/tumor blood vessel interaction by epi-illumination and 2-photon laser scanning microscopy. We further investigated cellular and tissue function, including the enzyme activity of intratumoral and microglial NADPH oxidase measured by in vivo fluorescence lifetime imaging. We identified three morphological phenotypes of tumor-associated microglia cells with entirely different motility patterns. We found that NADPH oxidase activation is highly divergent in these microglia subtypes leading to different production levels of reactive oxygen species (ROS). We observed that microglia motility is highest within the perivascular niche, suggesting relevance of microglia/tumor blood vessel interactions. In line, reduction of tumor blood vessels by antivascular therapy confirmed the relevance of the tumor vessel compartment on microglia biology in brain tumors. In summary, we provide new insights into in vivo microglial behavior, regarding both morphology and function, in malignant gliomas. GLIA 2016;64:1210-1226.
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Affiliation(s)
- Simon Heinrich Bayerl
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany
| | - Raluca Niesner
- German Rheumatism Research Center Berlin, Berlin, Germany, Charitéplatz 1, Berlin, Germany
| | - Zoltan Cseresnyes
- German Rheumatism Research Center Berlin, Berlin, Germany, Charitéplatz 1, Berlin, Germany
| | - Helena Radbruch
- Department of Neuropathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, Berlin, Germany
| | - Julian Pohlan
- German Rheumatism Research Center Berlin, Berlin, Germany, Charitéplatz 1, Berlin, Germany
| | - Susan Brandenburg
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany
| | - Marcus Alexander Czabanka
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany
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Tay TL, Hagemeyer N, Prinz M. The force awakens: insights into the origin and formation of microglia. Curr Opin Neurobiol 2016; 39:30-7. [PMID: 27107946 DOI: 10.1016/j.conb.2016.04.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 12/12/2022]
Abstract
Microglia are tissue resident macrophages of the central nervous system (CNS) that maintain homeostasis and respond to immune challenges. New genetic fate mapping tools have revealed a yolk sac origin of microglia. Once established in the CNS, microglia persist throughout the lifetime of the organism behind the blood-brain barrier and maintain themselves by self-renewal. Recent studies uncovered a broad spectrum of microglial functions that are influenced by the dynamism of brain formation and neuronal wiring. This review focuses on current findings concerning microglia origin and formation during development and discusses the factors important for microglia survival and function.
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Affiliation(s)
- Tuan Leng Tay
- Institute of Neuropathology, University of Freiburg, Germany
| | - Nora Hagemeyer
- Institute of Neuropathology, University of Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, University of Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, University of Freiburg, Germany.
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164
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Woodling NS, Andreasson KI. Untangling the Web: Toxic and Protective Effects of Neuroinflammation and PGE2 Signaling in Alzheimer's Disease. ACS Chem Neurosci 2016; 7:454-63. [PMID: 26979823 DOI: 10.1021/acschemneuro.6b00016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The neuroinflammatory response has received increasing attention as a key factor in the pathogenesis of Alzheimer's disease (AD). Microglia, the innate immune cells and resident phagocytes of the brain, respond to accumulating Aβ peptides by generating a nonresolving inflammatory response. While this response can clear Aβ peptides from the nervous system in some settings, its failure to do so in AD accelerates synaptic injury, neuronal loss, and cognitive decline. The complex molecular components of this response are beginning to be unraveled, with identification of both damaging and protective roles for individual components of the neuroinflammatory response. Even within one molecular pathway, contrasting effects are often present. As one example, recent studies of the inflammatory cyclooxygenase-prostaglandin pathway have revealed both beneficial and detrimental effects dependent on the disease context, cell type, and downstream signaling pathway. Nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit cyclooxygenases, are associated with reduced AD risk when taken by cognitively normal populations, but additional clinical and mouse model studies have added complexities and caveats to this finding. Downstream of cyclooxygenase activity, prostaglandin E2 signaling exerts both damaging pro-inflammatory and protective anti-inflammatory effects through actions of specific E-prostanoid G-protein coupled receptors on specific cell types. These complexities underscore the need for careful study of individual components of the neuroinflammatory response to better understand their contribution to AD pathogenesis and progression.
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Affiliation(s)
- Nathaniel S. Woodling
- Department of Neurology and
Neurological Sciences, Stanford University School of Medicine, 1201
Welch Road, Stanford, California 94305, United States
| | - Katrin I. Andreasson
- Department of Neurology and
Neurological Sciences, Stanford University School of Medicine, 1201
Welch Road, Stanford, California 94305, United States
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165
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Frost JL, Schafer DP. Microglia: Architects of the Developing Nervous System. Trends Cell Biol 2016; 26:587-597. [PMID: 27004698 DOI: 10.1016/j.tcb.2016.02.006] [Citation(s) in RCA: 234] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/16/2016] [Accepted: 02/19/2016] [Indexed: 11/18/2022]
Abstract
Microglia are resident macrophages of the central nervous system (CNS), representing 5-10% of total CNS cells. Recent findings reveal that microglia enter the embryonic brain, take up residence before the differentiation of other CNS cell types, and become critical regulators of CNS development. Here, we discuss exciting new work implicating microglia in a range of developmental processes, including regulation of cell number and spatial patterning of CNS cells, myelination, and formation and refinement of neural circuits. Furthermore, we review studies suggesting that these cellular functions result in the modulation of behavior, which has important implications for a variety of neurological disorders.
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Affiliation(s)
- Jeffrey L Frost
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Dorothy P Schafer
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
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166
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Solano Fonseca R, Mahesula S, Apple DM, Raghunathan R, Dugan A, Cardona A, O'Connor J, Kokovay E. Neurogenic Niche Microglia Undergo Positional Remodeling and Progressive Activation Contributing to Age-Associated Reductions in Neurogenesis. Stem Cells Dev 2016; 25:542-55. [PMID: 26857912 DOI: 10.1089/scd.2015.0319] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Neural stem cells (NSCs) exist throughout life in the ventricular-subventricular zone (V-SVZ) of the mammalian forebrain. During aging NSC function is diminished through an unclear mechanism. In this study, we establish microglia, the immune cells of the brain, as integral niche cells within the V-SVZ that undergo age-associated repositioning in the V-SVZ. Microglia become activated early before NSC deficits during aging resulting in an antineurogenic microenvironment due to increased inflammatory cytokine secretion. These age-associated changes were not observed in non-neurogenic brain regions, suggesting V-SVZ microglia are specialized. Using a sustained inflammatory model in young adult mice, we induced microglia activation and inflammation that was accompanied by reduced NSC proliferation in the V-SVZ. Furthermore, in vitro studies revealed secreted factors from activated microglia reduced proliferation and neuron production compared to secreted factors from resting microglia. Our results suggest that age-associated chronic inflammation contributes to declines in NSC function within the aging neurogenic niche.
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Affiliation(s)
- Rene Solano Fonseca
- 1 Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio , San Antonio, Texas.,2 Barshop Institute for Longevity and Aging Studies , San Antonio, Texas
| | - Swetha Mahesula
- 1 Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Deana M Apple
- 1 Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio , San Antonio, Texas.,2 Barshop Institute for Longevity and Aging Studies , San Antonio, Texas
| | - Rekha Raghunathan
- 3 Molecular and Translational Medicine, Boston University , Boston, Massachusetts
| | - Allison Dugan
- 4 Department of Pharmacology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Astrid Cardona
- 5 Department of Biology, University of Texas at San Antonio , San Antonio, Texas
| | - Jason O'Connor
- 4 Department of Pharmacology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Erzsebet Kokovay
- 1 Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio , San Antonio, Texas.,2 Barshop Institute for Longevity and Aging Studies , San Antonio, Texas
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167
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Auvynet C, Baudesson de Chanville C, Hermand P, Dorgham K, Piesse C, Pouchy C, Carlier L, Poupel L, Barthélémy S, Felouzis V, Lacombe C, Sagan S, Chemtob S, Quiniou C, Salomon B, Deterre P, Sennlaub F, Combadière C. ECL1i, d(LGTFLKC), a novel, small peptide that specifically inhibits CCL2-dependent migration. FASEB J 2016; 30:2370-81. [PMID: 26979087 DOI: 10.1096/fj.201500116] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/25/2016] [Indexed: 11/11/2022]
Abstract
CC chemokine receptor type 2 (CCR2) is a key molecule in inflammatory diseases and is an obvious drug target for the treatment of inflammation. A number of nonpeptidic, competitive CCR2 antagonists have been developed, but none has yet been approved for clinical use. Our aim was to identify a short peptide that showed allosteric antagonism against human and mouse CCR2. On the basis of sequence analysis and 3-dimensional modeling, we identified an original 7-d-amino acid peptidic CCR2 inhibitor that we have called extracellular loop 1 inverso (ECL1i), d(LGTFLKC). In vitro, ECL1i selectively and potently inhibits CC chemokine ligand type 2 (CCL2)-triggered chemotaxis (IC50, 2 µM) but no other conventional CCL2-associated events. We used the classic competitive CCR2 antagonist, BMS22 {2-[(isopropylaminocarbonyl)amino]-N-[2-[[cis-2-[[4-(methylthio)benzoyl]amino]cyclohexyl]amino]-2-oxoethyl]-5-(trifluoromethyl)benzamide}, as positive control and inhibited CCL2-dependent chemotaxis with an IC50 of 18 nM. As negative control, we used a peptide with the same composition as ECL1i, but in a different sequence, d(FKLTLCG). In vivo, ECL1i (4 mg/kg) interfered with CCR2-positive cell recruitment and attenuated disease progression in experimental autoimmune encephalomyelitis, a mouse model of multiple sclerosis. This study establishes ECL1i as the first allosteric inhibitor of CCR2 with functional selectivity. ECL1i is a promising new agent in therapeutic development, and it may, by its selective effect, increase our understanding of CCR2 signaling pathways and functions.-Auvynet, C., Baudesson de Chanville, C., Hermand, P., Dorgham, K., Piesse, C., Pouchy, C., Carlier, L., Poupel, L., Barthélémy, S., Felouzis, V., Lacombe, C., Sagan, S., Salomon, B., Deterre, P., Sennlaub, F., Combadière, C. ECL1i, d(LGTFLKC), a novel, small peptide that specifically inhibits CCL2-dependent migration.
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Affiliation(s)
- Constance Auvynet
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Camille Baudesson de Chanville
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Patricia Hermand
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Karim Dorgham
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Christophe Piesse
- Sorbonne Universités, UPMC/Univ Paris 06, Institut de Biologie Paris-Seine (IBPS) 3631, CNRS, Service de Synthése Peptidique, Paris, France
| | - Charlotte Pouchy
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Ludovic Carlier
- Sorbonne Universités, UPMC/Univ Paris 06, CNRS, UMR 7203, Laboratoire des Biomolécules, Paris, France
| | - Lucie Poupel
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Sandrine Barthélémy
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Virginie Felouzis
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Claire Lacombe
- Sorbonne Universités, UPMC/Univ Paris 06, CNRS, UMR 7203, Laboratoire des Biomolécules, Paris, France; Ecole Normale Supérieure-Université de Recherche Paris Sciences et Lettres, Département de Chimie, Paris, France; Faculté des Sciences et Technologie, Université Paris Est Créteil-Val de Marne, Créteil, France
| | - Sandrine Sagan
- Sorbonne Universités, UPMC/Univ Paris 06, CNRS, UMR 7203, Laboratoire des Biomolécules, Paris, France
| | | | | | - Benoit Salomon
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Philippe Deterre
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France
| | - Florian Sennlaub
- Sorbonne Universités, UPMC/ Univ Paris 06, UMRS 968, INSERM, U968, Institut de la Vision, Paris, France; Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-Direction des Hôpitaux et de l'Offre de Soins (DHOS), Centre d'Investigation Clinique 503, Paris, France
| | - Christophe Combadière
- *Sorbonne Universités, Université Pierre et Marie Curie (UPMC)/Univ Paris 06, Unité Mixte de Recherche Scientifique (UMRS) 1135, INSERM Unité 1135, Centre National de la Recherche Scientifique, Equipe de Recherche Labellisée (ERL) 8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France;
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168
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Double Roles of Macrophages in Human Neuroimmune Diseases and Their Animal Models. Mediators Inflamm 2016; 2016:8489251. [PMID: 27034594 PMCID: PMC4808549 DOI: 10.1155/2016/8489251] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 02/21/2016] [Accepted: 02/23/2016] [Indexed: 12/22/2022] Open
Abstract
Macrophages are important immune cells of the innate immune system that are involved in organ-specific homeostasis and contribute to both pathology and resolution of diseases including infections, cancer, obesity, atherosclerosis, and autoimmune disorders. Multiple lines of evidence point to macrophages as a remarkably heterogeneous cell type. Different phenotypes of macrophages exert either proinflammatory or anti-inflammatory roles depending on the cytokines and other mediators that they are exposed to in the local microenvironment. Proinflammatory macrophages secrete detrimental molecules to induce disease development, while anti-inflammatory macrophages produce beneficial mediators to promote disease recovery. The conversion of the phenotypes of macrophages can regulate the initiation, development, and recovery of autoimmune diseases. Human neuroimmune diseases majorly include multiple sclerosis (MS), neuromyelitis optica (NMO), myasthenia gravis (MG), and Guillain-Barré syndrome (GBS) and macrophages contribute to the pathogenesis of these neuroimmune diseases. In this review, we summarize the double roles of macrophage in neuroimmune diseases and their animal models to further explore the mechanisms of macrophages involved in the pathogenesis of these disorders, which may provide a potential therapeutic approach for these disorders in the future.
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169
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Dudvarski Stankovic N, Teodorczyk M, Ploen R, Zipp F, Schmidt MHH. Microglia-blood vessel interactions: a double-edged sword in brain pathologies. Acta Neuropathol 2016; 131:347-63. [PMID: 26711460 DOI: 10.1007/s00401-015-1524-y] [Citation(s) in RCA: 194] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/09/2015] [Accepted: 12/12/2015] [Indexed: 12/12/2022]
Abstract
Microglia are long-living resident immune cells of the brain, which secure a stable chemical and physical microenvironment necessary for the proper functioning of the central nervous system (CNS). These highly dynamic cells continuously scan their environment for pathogens and possess the ability to react to damage-induced signals in order to protect the brain. Microglia, together with endothelial cells (ECs), pericytes and astrocytes, form the functional blood-brain barrier (BBB), a specialized endothelial structure that selectively separates the sensitive brain parenchyma from blood circulation. Microglia are in bidirectional and permanent communication with ECs and their perivascular localization enables them to survey the influx of blood-borne components into the CNS. Furthermore, they may stimulate the opening of the BBB, extravasation of leukocytes and angiogenesis. However, microglia functioning requires tight control as their dysregulation is implicated in the initiation and progression of numerous neurological diseases. Disruption of the BBB, changes in blood flow, introduction of pathogens in the sensitive CNS niche, insufficient nutrient supply, and abnormal secretion of cytokines or expression of endothelial receptors are reported to prime and attract microglia. Such reactive microglia have been reported to even escalate the damage of the brain parenchyma as is the case in ischemic injuries, brain tumors, multiple sclerosis, Alzheimer's and Parkinson's disease. In this review, we present the current state of the art of the causes and mechanisms of pathological interactions between microglia and blood vessels and explore the possibilities of targeting those dysfunctional interactions for the development of future therapeutics.
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Affiliation(s)
- Nevenka Dudvarski Stankovic
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
- German Cancer Consortium (DKTK), Heidelberg, Germany.
- German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Marcin Teodorczyk
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
| | - Robert Ploen
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Research Center for Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
| | - Frauke Zipp
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Research Center for Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
| | - Mirko H H Schmidt
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
- German Cancer Consortium (DKTK), Heidelberg, Germany.
- German Cancer Research Center (DKFZ), Heidelberg, Germany.
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170
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Xing Z, Xia Z, Peng W, Li J, Zhang C, Fu C, Tang T, Luo J, Zou Y, Fan R, Liu W, Xiong X, Huang W, Sheng C, Gan P, Wang Y. Xuefu Zhuyu decoction, a traditional Chinese medicine, provides neuroprotection in a rat model of traumatic brain injury via an anti-inflammatory pathway. Sci Rep 2016; 6:20040. [PMID: 26818584 PMCID: PMC4730240 DOI: 10.1038/srep20040] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/23/2015] [Indexed: 12/28/2022] Open
Abstract
Neuroinflammation is central to the pathology of traumatic brain injury (TBI). Xuefu Zhuyu decoction (XFZY) is an effective traditional Chinese medicine to treat TBI. To elucidate its potential molecular mechanism, this study aimed to demonstrate that XFZY functions as an anti-inflammatory agent by inhibiting the PI3K-AKT-mTOR pathway. Sprague-Dawley rats were exposed to controlled cortical impact to produce a neuroinflammatory response. The treatment groups received XFZY (9 g/kg and 18 g/kg), Vehicle group and Sham group were gavaged with equal volumes of saline. The modified neurologic severity score (mNSS) and the Morris water maze test were used to assess neurological deficits. Arachidonic acid (AA) levels in brain tissue were measured using tandem gas chromatography-mass spectrometry. TNF-α and IL-1β levels in injured ipsilateral brain tissue were detected by ELISA. AKT and mTOR expression were measured by western blot analysis. The results indicated that XFZY significantly enhanced spatial memory acquisition. XFZY (especially at a dose of 9 g/kg) markedly reduced the mNSS and levels of AA, TNF-α and IL-1β. Significant downregulation of AKT/mTOR/p70S6K proteins in brain tissues was observed after the administration of XFZY (especially at a dose of 9 g/kg). XFZY may be a promising therapeutic strategy for reducing inflammation in TBI.
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Affiliation(s)
- Zhihua Xing
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Zian Xia
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Weijun Peng
- Department of traditional Chinese medicine, 2nd Xiangya Hospital, Central South University, 410011 Changsha, China
| | - Jun Li
- Thyroid Tumour Internal Medicine Department, Cancer Hospital affiliated to Xiangya School of Medicine, Central South University, 410013 Changsha, China
| | - Chunhu Zhang
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Chunyan Fu
- Department of Pharmacy, Shaoyang Medical College Level Specialty School, 422000 Shaoyang, China
| | - Tao Tang
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Jiekun Luo
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Yong Zou
- Department of Gerontology and Respiratory Diseases, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Rong Fan
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Weiping Liu
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Xingui Xiong
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Wei Huang
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Chenxia Sheng
- Department of traditional Chinese medicine, 2nd Xiangya Hospital, Central South University, 410011 Changsha, China
| | - Pingping Gan
- Department of Oncology, Xiangya Hospital, Central South University, 410008 Changsha, China
| | - Yang Wang
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, 410008 Changsha, China
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171
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Stress and neuroinflammation: a systematic review of the effects of stress on microglia and the implications for mental illness. Psychopharmacology (Berl) 2016; 233:1637-50. [PMID: 26847047 PMCID: PMC4828495 DOI: 10.1007/s00213-016-4218-9] [Citation(s) in RCA: 426] [Impact Index Per Article: 53.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 01/18/2016] [Indexed: 01/19/2023]
Abstract
RATIONALE Psychosocial stressors are a well-documented risk factor for mental illness. Neuroinflammation, in particular elevated microglial activity, has been proposed to mediate this association. A number of preclinical studies have investigated the effect of stress on microglial activity. However, these have not been systematically reviewed before. OBJECTIVES This study aims to systematically review the effects of stress on microglia, as indexed by the histological microglial marker ionised calcium binding adaptor molecule 1 (Iba-1), and consider the implications of these for the role of stress in the development of mental disorders. METHODS A systematic review was undertaken using pre-defined search criteria on PubMed and EMBASE. Inclusion and data extraction was agreed by two independent researchers after review of abstracts and full text. RESULTS Eighteen studies met the inclusion criteria. These used seven different psychosocial stressors, including chronic restraint, social isolation and repeated social defeat in gerbils, mice and/or rats. The hippocampus (11/18 studies) and prefrontal cortex (13/18 studies) were the most frequently studied areas. Within the hippocampus, increased Iba-1 levels of between 20 and 200 % were reported by all 11 studies; however, one study found this to be a duration-dependent effect. Of those examining the prefrontal cortex, ∼75 % found psychosocial stress resulted in elevated Iba-1 activity. Elevations were also consistently seen in the nucleus accumbens, and under some stress conditions in the amygdala and paraventricular nucleus. CONCLUSIONS There is consistent evidence that a range of psychosocial stressors lead to elevated microglial activity in the hippocampus and good evidence that this is also the case in other brain regions. These effects were seen with early-life/prenatal stress, as well as stressors in adulthood. We consider these findings in terms of the two-hit hypothesis, which proposes that early-life stress primes microglia, leading to a potentiated response to subsequent stress. The implications for understanding the pathoaetiology of mental disorders and the development of new treatments are also considered.
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172
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Abstract
Macrophages are myeloid immune cells that are strategically positioned throughout the body tissues, where they ingest and degrade dead cells, debris, and foreign material and orchestrate inflammatory processes. Here we review two major recent paradigm shifts in our understanding of tissue macrophage biology. The first is the realization that most tissue-resident macrophages are established prenatally and maintained through adulthood by longevity and self-renewal. Their generation and maintenance are thus independent from ongoing hematopoiesis, although the cells can be complemented by adult monocyte-derived macrophages. Second, aside from being immune sentinels, tissue macrophages form integral components of their host tissue. This entails their specialization in response to local environmental cues to contribute to the development and specific function of their tissue of residence. Factors that govern tissue macrophage specialization are emerging. Moreover, tissue specialization is reflected in discrete gene expression profiles of macrophages, as well as epigenetic signatures reporting actual and potential enhancer usage.
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Affiliation(s)
- Chen Varol
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 64239, Israel
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173
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Xu L, He D, Bai Y. Microglia-Mediated Inflammation and Neurodegenerative Disease. Mol Neurobiol 2015; 53:6709-6715. [PMID: 26659872 DOI: 10.1007/s12035-015-9593-4] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 12/01/2015] [Indexed: 02/06/2023]
Abstract
Microglia are the main effectors in the inflammatory process of the central nervous system. As the first line of defense, microglia play an important role in the inflammatory reaction. When there is pathogen invasion or cell debris, microglia will be activated rapidly and remove it, while releasing the inflammatory cytokines to mediate inflammatory reaction. Activated microglia were found surrounding lesions of various neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, muscular amyotrophic lateral sclerosis, and multiple sclerosis. Microglia, the effectors of neuronal degeneration and necrosis, are involved in the removal of necrotic neurons. But over activated microglia may accelerate the process of some neurodegenerative diseases. Activated microglia can release cytotoxic factor and cytokines. Some of them may cause further damage to neuron, and some of them can regulate inflammatory cells to gather to the lesion. Microglia-mediated inflammation was considered to be the possible mechanism for the occurrence or deterioration of neurodegenerative diseases. Therefore, inhibiting the activity of microglia appropriately may be an effective way for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Ling Xu
- The Department of Neurology, Xin Hua Hospital Affiliated Dalian University, Dalian University, Dalian, 116021, China
| | - Dan He
- Department of Cardiology, The Second Affiliated Hospital of Dalian Medical University, Dalian, 116022, China
| | - Ying Bai
- The Department of Neurology, Xin Hua Hospital Affiliated Dalian University, Dalian University, Dalian, 116021, China.
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174
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Central nervous system myeloid cells as drug targets: current status and translational challenges. Nat Rev Drug Discov 2015; 15:110-24. [DOI: 10.1038/nrd.2015.14] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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175
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Arnold L, Perrin H, de Chanville CB, Saclier M, Hermand P, Poupel L, Guyon E, Licata F, Carpentier W, Vilar J, Mounier R, Chazaud B, Benhabiles N, Boissonnas A, Combadiere B, Combadiere C. CX3CR1 deficiency promotes muscle repair and regeneration by enhancing macrophage ApoE production. Nat Commun 2015; 6:8972. [PMID: 26632270 PMCID: PMC4686853 DOI: 10.1038/ncomms9972] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/21/2015] [Indexed: 01/22/2023] Open
Abstract
Muscle injury triggers inflammation in which infiltrating mononuclear phagocytes are crucial for tissue regeneration. The interaction of the CCL2/CCR2 and CX3CL1/CX3CR1 chemokine axis that guides phagocyte infiltration is incompletely understood. Here, we show that CX3CR1 deficiency promotes muscle repair and rescues Ccl2−/− mice from impaired muscle regeneration as a result of altered macrophage function, not infiltration. Transcriptomic analysis of muscle mononuclear phagocytes reveals that Apolipoprotein E (ApoE) is upregulated in mice with efficient regeneration. ApoE treatment enhances phagocytosis by mononuclear phagocytes in vitro, and restores phagocytic activity and muscle regeneration in Ccl2−/− mice. Because CX3CR1 deficiency may compensate for defective CCL2-dependant monocyte recruitment by modulating ApoE-dependent macrophage phagocytic activity, targeting CX3CR1 expressed by macrophages might be a powerful therapeutic approach to improve muscle regeneration. Chemokine-driven infiltration of inflammatory macrophages is central to the muscle regenerative response to injury. Here the authors show that the function of infiltrating macrophages is also important as notexin-induced muscle injury in mice is rescued by CX3CR1 knockout owing to enhanced ApoE production.
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Affiliation(s)
- Ludovic Arnold
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Hélène Perrin
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Camille Baudesson de Chanville
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Marielle Saclier
- Inserm, U1016, Institut Cochin, 22 Rue Méchain, F-75014 Paris, France.,CNRS, UMR8104, 22 Rue Méchain, F-75014 Paris, France.,University of Paris Descartes, Sorbonne Paris Cite, F-75006 Paris, France
| | - Patricia Hermand
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Lucie Poupel
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Elodie Guyon
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Fabrice Licata
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Wassila Carpentier
- Sorbonne Universités, UPMC Univ Paris 06, Plateforme Post-Génomique de la Pitié-Salpêtrière (P3S), UMS2 Omique, INSERM US029, 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - José Vilar
- Paris Centre de Recherche Cardiovasculaire (PARCC) - HEGP, 56 Rue Leblanc, F-75015 Paris, France
| | - Rémi Mounier
- Inserm, U1016, Institut Cochin, 22 Rue Méchain, F-75014 Paris, France.,CNRS, UMR8104, 22 Rue Méchain, F-75014 Paris, France.,University of Paris Descartes, Sorbonne Paris Cite, F-75006 Paris, France
| | - Bénédicte Chazaud
- Inserm, U1016, Institut Cochin, 22 Rue Méchain, F-75014 Paris, France.,CNRS, UMR8104, 22 Rue Méchain, F-75014 Paris, France.,University of Paris Descartes, Sorbonne Paris Cite, F-75006 Paris, France
| | - Nora Benhabiles
- CEA, List institute CEA Saclay, Digitéo Labs, PC192, F-91191 Gif-sur-Yvette, Cedex, France
| | - Alexandre Boissonnas
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Béhazine Combadiere
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Christophe Combadiere
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, U1135, CNRS, ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Boulevard de l'Hôpital, F-75013 Paris, France
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Abstract
Glioblastomas (GBM) are one of the most recalcitrant brain tumors because of their aggressive invasive growth and resistance to therapy. They are highly heterogeneous malignancies at both the molecular and histological levels. Specific histological hallmarks including pseudopalisading necrosis and microvascular proliferation distinguish GBM from lower-grade gliomas, and make GBM one of the most hypoxic as well as angiogenic tumors. These microanatomical compartments present specific niches within the tumor microenvironment that regulate metabolic needs, immune surveillance, survival, invasion as well as cancer stem cell maintenance. Here we review features and functions of the distinct GBM niches, detail the different cell constituents and the functional status of the vasculature, and discuss prospects of therapeutically targeting GBM niche constituents.
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Affiliation(s)
- Dolores Hambardzumyan
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
| | - Gabriele Bergers
- Department of Neurological Surgery, University of California San Francisco, Helen Diller Family Cancer Research Center, 1450 3 Street, San Francisco, California 94158, USA; Brain Tumor Center, University of California San Francisco, Helen Diller Family Cancer Research Center, 1450 3 Street, San Francisco, California 94158, USA; UCSF Comprehensive Cancer Center, University of California San Francisco, Helen Diller Family Cancer Research Center, 1450 3 Street, San Francisco, California 94158, USA
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177
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Chen M, Xu H. Parainflammation, chronic inflammation, and age-related macular degeneration. J Leukoc Biol 2015; 98:713-25. [PMID: 26292978 PMCID: PMC4733662 DOI: 10.1189/jlb.3ri0615-239r] [Citation(s) in RCA: 251] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/28/2015] [Indexed: 12/13/2022] Open
Abstract
Inflammation is an adaptive response of the immune system to noxious insults to maintain homeostasis and restore functionality. The retina is considered an immune-privileged tissue as a result of its unique anatomic and physiologic properties. During aging, the retina suffers from a low-grade chronic oxidative insult, which sustains for decades and increases in level with advancing age. As a result, the retinal innate-immune system, particularly microglia and the complement system, undergoes low levels of activation (parainflammation). In many cases, this parainflammatory response can maintain homeostasis in the healthy aging eye. However, in patients with age-related macular degeneration, this parainflammatory response becomes dysregulated and contributes to macular damage. Factors contributing to the dysregulation of age-related retinal parainflammation include genetic predisposition, environmental risk factors, and old age. Dysregulated parainflammation (chronic inflammation) in age-related macular degeneration damages the blood retina barrier, resulting in the breach of retinal-immune privilege, leading to the development of retinal lesions. This review discusses the basic principles of retinal innate-immune responses to endogenous chronic insults in normal aging and in age-related macular degeneration and explores the difference between beneficial parainflammation and the detrimental chronic inflammation in the context of age-related macular degeneration.
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Affiliation(s)
- Mei Chen
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, United Kingdom
| | - Heping Xu
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, United Kingdom
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178
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Fractalkine Signaling Regulates the Inflammatory Response in an α-Synuclein Model of Parkinson Disease. PLoS One 2015; 10:e0140566. [PMID: 26469270 PMCID: PMC4607155 DOI: 10.1371/journal.pone.0140566] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/28/2015] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Parkinson disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopamine neurons in the substantia nigra pars compacta (SNpc) and widespread aggregates of the protein alpha-synuclein (α-syn). Increasing evidence points to inflammation as a chief mediator; however, the role of α-syn in triggering and sustaining inflammation remains unclear. In models of Alzheimer's disease (AD), multiple sclerosis (MS) and neurotoxin models of PD, the chemokine CX3CL1 (fractalkine) and its receptor (CX3CR1) have important roles in modulating neuroinflammation. METHODS To examine the role of fractalkine signaling in α-syn-induced-neuroinflammation and neurodegeneration, we used an in vivo mouse model in which human α-syn is overexpressed by an adeno associated viral vector serotype 2 (AAV2) and in vitro phagocytosis and protein internalization assays with primary microglia treated with aggregated α-syn. RESULTS We observed that loss of CX3CR1 expression led to a reduced inflammatory response, with reduced IgG deposition and expression of MHCII 4 weeks post-transduction. Six months post transduction, AAV2 mediated overexpression of α-syn leads to loss of dopaminergic neurons, and this loss was not exacerbated in animals with deletion of CX3CR1. To determine the mechanism by which CX3CR1affects inflammatory responses in α-syn-induced inflammation, phagocytosis was assessed using a fluorescent microsphere assay as well as by microglial uptake of aggregated α-syn. CX3CR1-/- microglia showed reduced uptake of fluorescent beads and aggregated α-syn. CONCLUSION Our results suggest that one mechanism by which CX3CR1-/- attenuates inflammation is at the level of phagocytosis of aggregated α-syn by microglia. These data implicate fractalkine signaling as a potential therapeutic target for regulating inflammatory response in α-syn models PD.
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179
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Kohno H, Koso H, Okano K, Sundermeier TR, Saito S, Watanabe S, Tsuneoka H, Sakai T. Expression pattern of Ccr2 and Cx3cr1 in inherited retinal degeneration. J Neuroinflammation 2015; 12:188. [PMID: 26458944 PMCID: PMC4603985 DOI: 10.1186/s12974-015-0408-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 10/02/2015] [Indexed: 12/27/2022] Open
Abstract
Background Though accumulating evidence suggests that microglia, resident macrophages in the retina, and bone marrow-derived macrophages can cause retinal inflammation which accelerates photoreceptor cell death, the details of how these cells are activated during retinal degeneration (RD) remain uncertain. Therefore, it is important to clarify which cells play a dominant role in fueling retinal inflammation. However, distinguishing between microglia and macrophages is difficult using conventional techniques such as cell markers (e.g., Iba-1). Recently, two mouse models for visualizing chemokine receptors were established, Cx3cr1GFP/GFP and Ccr2RFP/RFP mice. As Cx3cr1 is expressed in microglia and Ccr2 is reportedly expressed in activated macrophages, these mice have the potential to distinguish microglia and macrophages, yielding novel information about the activation of these inflammatory cells and their individual roles in retinal inflammation. Methods In this study, c-mer proto-oncogene tyrosine kinase (Mertk)−/− mice, which show photoreceptor cell death due to defective retinal pigment epithelium phagocytosis, were employed as an animal model of RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were established by breeding Mertk−/−, Cx3cr1GFP/GFP, and Ccr2RFP/RFP mice. The retinal morphology and pattern of inflammatory cell activation and invasion of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were evaluated using retina and retinal pigment epithelium (RPE) flat mounts, retinal sections, and flow cytometry. Results Four-week-old Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice showed Cx3cr1-GFP-positive microglia in the inner retina. Cx3cr1-GFP and Ccr2-RFP dual positive activated microglia were observed in the outer retina and subretinal space of 6- and 8-week-old animals. Ccr2-RFP single positive bone marrow-derived macrophages were observed to migrate into the retina of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. These invading cells were still observed in the subretinal space in 18-week-old animals. Conclusions Cx3cr1-GFP-positive microglia and Ccr2-RFP-positive macrophages were distinguishable in the retinas of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. In addition, Ccr2 expression in Cx3cr1 positive microglia is a feature of microglial activation in RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice enabled observation of microglial activation over time during RD and may be useful for developing inflammation-targeted treatment strategies for RD in the future.
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Affiliation(s)
- Hideo Kohno
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan. .,Tokyu Hospital, 145-0062, Tokyo, Japan.
| | - Hideto Koso
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Kiichiro Okano
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Thomas R Sundermeier
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Saburo Saito
- Department of Molecular Immunology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Hiroshi Tsuneoka
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Tsutomu Sakai
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan.
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180
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Homeostasis of Microglia in the Adult Brain: Review of Novel Microglia Depletion Systems. Trends Immunol 2015; 36:625-636. [DOI: 10.1016/j.it.2015.08.005] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 01/16/2023]
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181
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Abstract
Microglia, the major myeloid cells of the central nervous system (CNS) are implicated in physiologic processes and in the pathogenesis of several CNS disorders. Since their initial description early in the 20th century, our ability to identify and isolate microglia has significantly improved and new research is providing insight into the functions of these cells in sickness and in health. Here, we review recent advances in our understanding of the role of microglia in physiological and pathological processes of the CNS with a focus on multiple sclerosis and Alzheimer's disease. Because of the prominent roles CX3CR1 and its ligand fractalkine played in bringing about these advances, we discuss the physiological and pathological roles of microglia as viewed from the CX3CR1-fractalkine perspective, providing a unique viewpoint. Based on the most recent studies of molecular profiling of microglia, we also propose a molecular and functional definition of microglia that incorporates the properties attributed to these cells in recent years.
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Affiliation(s)
- Richard M Ransohoff
- Neuroinflammation Research Center, Department of Neurosciences, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195
| | - Joseph El Khoury
- Division of Infectious Diseases and Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129
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182
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Wlodarczyk A, Cédile O, Jensen KN, Jasson A, Mony JT, Khorooshi R, Owens T. Pathologic and Protective Roles for Microglial Subsets and Bone Marrow- and Blood-Derived Myeloid Cells in Central Nervous System Inflammation. Front Immunol 2015; 6:463. [PMID: 26441968 PMCID: PMC4562247 DOI: 10.3389/fimmu.2015.00463] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/25/2015] [Indexed: 12/13/2022] Open
Abstract
Inflammation is a series of processes designed for eventual clearance of pathogens and repair of damaged tissue. In the context of autoimmune recognition, inflammatory processes are usually considered to be pathological. This is also true for inflammatory responses in the central nervous system (CNS). However, as in other tissues, neuroinflammation can have beneficial as well as pathological outcomes. The complex role of encephalitogenic T cells in multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE) may derive from heterogeneity of the myeloid cells with which these T cells interact within the CNS. Myeloid cells, including resident microglia and infiltrating bone marrow-derived cells, such as dendritic cells (DC) and monocytes/macrophages [bone marrow-derived macrophages (BMDM)], are highly heterogeneous populations that may be involved in neurotoxicity and also immunoregulation and regenerative processes. Better understanding and characterization of myeloid cell heterogeneity is essential for future development of treatments controlling inflammation and inducing neuroprotection and neuroregeneration in diseased CNS. Here, we describe and compare three populations of myeloid cells: CD11c+ microglia, CD11c− microglia, and CD11c+ blood-derived cells in terms of their pathological versus protective functions in the CNS of mice with EAE. Our data show that CNS-resident microglia include functionally distinct subsets that can be distinguished by their expression of CD11c. These subsets differ in their expression of Arg-1, YM1, iNOS, IL-10, and IGF-1. Moreover, in contrast to BMDM/DC, both subsets of microglia express protective interferon-beta (IFNβ), high levels of colony-stimulating factor-1 receptor, and do not express the Th1-associated transcription factor T-bet. Taken together, our data suggest that CD11c+ microglia, CD11c− microglia, and infiltrating BMDM/DC represent separate and distinct populations and illustrate the heterogeneity of the CNS inflammatory environment.
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Affiliation(s)
- Agnieszka Wlodarczyk
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark , Odense , Denmark
| | - Oriane Cédile
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark , Odense , Denmark
| | - Kirstine Nolling Jensen
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark , Odense , Denmark
| | - Agathe Jasson
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark , Odense , Denmark ; Department of Biology, École Normale Supérieure de Lyon , Lyon , France
| | - Jyothi Thyagabhavan Mony
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark , Odense , Denmark
| | - Reza Khorooshi
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark , Odense , Denmark
| | - Trevor Owens
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark , Odense , Denmark
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183
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Febinger HY, Thomasy HE, Pavlova MN, Ringgold KM, Barf PR, George AM, Grillo JN, Bachstetter AD, Garcia JA, Cardona AE, Opp MR, Gemma C. Time-dependent effects of CX3CR1 in a mouse model of mild traumatic brain injury. J Neuroinflammation 2015; 12:154. [PMID: 26329692 PMCID: PMC4557842 DOI: 10.1186/s12974-015-0386-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 08/20/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neuroinflammation is an important secondary mechanism that is a key mediator of the long-term consequences of neuronal injury that occur in traumatic brain injury (TBI). Microglia are highly plastic cells with dual roles in neuronal injury and recovery. Recent studies suggest that the chemokine fractalkine (CX3CL1, FKN) mediates neural/microglial interactions via its sole receptor CX3CR1. CX3CL1/CX3CR1 signaling modulates microglia activation, and depending upon the type and time of injury, either protects or exacerbates neurological diseases. METHODS In this study, mice deficient in CX3CR1 were subjected to mild controlled cortical impact injury (CCI), a model of TBI. We evaluated the effects of genetic deletion of CX3CR1 on histopathology, cell death/survival, microglia activation, and cognitive function for 30 days post-injury. RESULTS During the acute post-injury period (24 h-15 days), motor deficits, cell death, and neuronal cell loss were more profound in injured wild-type than in CX3CR1(-/-) mice. In contrast, during the chronic period of 30 days post-TBI, injured CX3CR1(-/-) mice exhibited greater cognitive dysfunction and increased neuronal death than wild-type mice. The protective and deleterious effects of CX3CR1 were associated with changes in microglia phenotypes; during the acute phase CX3CR1(-/-) mice showed a predominant anti-inflammatory M2 microglial response, with increased expression of Ym1, CD206, and TGFβ. In contrast, increased M1 phenotypic microglia markers, Marco, and CD68 were predominant at 30 days post-TBI. CONCLUSION Collectively, these novel data demonstrate a time-dependent role for CX3CL1/CX3CR1 signaling after TBI and suggest that the acute and chronic responses to mild TBI are modulated in part by distinct microglia phenotypes.
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Affiliation(s)
- Heidi Y Febinger
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA.,Present address: Interdepartmental Program in Neuroscience, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Hannah E Thomasy
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA.,Neuroscience Graduate Program, University of Washington, Seattle, WA, 98104, USA
| | - Maria N Pavlova
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA
| | - Kristyn M Ringgold
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA
| | - Paulien R Barf
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA
| | - Amrita M George
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA
| | - Jenna N Grillo
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA.,Department of Biology, University of Washington, Seattle, WA, 98104, USA
| | - Adam D Bachstetter
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, 40536, USA
| | - Jenny A Garcia
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Astrid E Cardona
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Mark R Opp
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA
| | - Carmelina Gemma
- Department of Anesthesiology and Pain Medicine, University of Washington, BOX # 359724, Seattle, WA, 98001, USA.
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184
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Abstract
Neuroglia, the "glue" that fills the space between neurons in the central nervous system, takes active part in nerve cell signaling. Neuroglial cells, astroglia, oligodendroglia, and microglia, are together about as numerous as neurons in the brain as a whole, and in the cerebral cortex grey matter, but the proportion varies widely among brain regions. Glial volume, however, is less than one-fifth of the tissue volume in grey matter. When stimulated by neurons or other cells, neuroglial cells release gliotransmitters by exocytosis, similar to neurotransmitter release from nerve endings, or by carrier-mediated transport or channel flux through the plasma membrane. Gliotransmitters include the common neurotransmitters glutamate and GABA, the nonstandard amino acid d-serine, the high-energy phosphate ATP, and l-lactate. The latter molecule is a "buffer" between glycolytic and oxidative metabolism as well as a signaling substance recently shown to act on specific lactate receptors in the brain. Complementing neurotransmission at a synapse, neuroglial transmission often implies diffusion of the transmitter over a longer distance and concurs with the concept of volume transmission. Transmission from glia modulates synaptic neurotransmission based on energetic and other local conditions in a volume of tissue surrounding the individual synapse. Neuroglial transmission appears to contribute significantly to brain functions such as memory, as well as to prevalent neuropathologies.
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Affiliation(s)
- Vidar Gundersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Jon Storm-Mathisen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Linda Hildegard Bergersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
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Closed head injury in an age-related Alzheimer mouse model leads to an altered neuroinflammatory response and persistent cognitive impairment. J Neurosci 2015; 35:6554-69. [PMID: 25904805 DOI: 10.1523/jneurosci.0291-15.2015] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Epidemiological studies have associated increased risk of Alzheimer's disease (AD)-related clinical symptoms with a medical history of head injury. Currently, little is known about pathophysiology mechanisms linked to this association. Persistent neuroinflammation is one outcome observed in patients after a single head injury. Neuroinflammation is also present early in relevant brain regions during AD pathology progression. In addition, previous mechanistic studies in animal models link neuroinflammation as a contributor to neuropathology and cognitive impairment in traumatic brain injury (TBI) or AD-related models. Therefore, we explored the potential interplay of neuroinflammatory responses in TBI and AD by analysis of the temporal neuroinflammatory changes after TBI in an AD model, the APP/PS1 knock-in (KI) mouse. Discrete temporal aspects of astrocyte, cytokine, and chemokine responses in the injured KI mice were delayed compared with the injured wild-type mice, with a peak neuroinflammatory response in the injured KI mice occurring at 7 d after injury. The neuroinflammatory responses were more persistent in the injured KI mice, leading to a chronic neuroinflammation. At late time points after injury, KI mice exhibited a significant impairment in radial arm water maze performance compared with sham KI mice or injured wild-type mice. Intervention with a small-molecule experimental therapeutic (MW151) that selectively attenuates proinflammatory cytokine production yielded improved cognitive behavior outcomes, consistent with a link between neuroinflammatory responses and altered risk for AD-associated pathology changes with head injury.
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186
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Kim SJ, Lee HJ, Yun JH, Ko JH, Choi DY, Oh JY. Intravitreal TSG-6 suppresses laser-induced choroidal neovascularization by inhibiting CCR2+ monocyte recruitment. Sci Rep 2015; 5:11872. [PMID: 26149224 PMCID: PMC4493567 DOI: 10.1038/srep11872] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/09/2015] [Indexed: 12/29/2022] Open
Abstract
Choroidal neovascularization (CNV) is the hallmark of wet age-related macular degeneration (AMD), one of the leading causes of blindness in the elderly. Although the pathogenesis of CNV is not clear, a number of studies show that ocular-infiltrating macrophages and inflammation play a critical role in the development of CNV. TNFα-stimulated gene/protein (TSG)-6 is a multifunctional endogenous protein that has anti-inflammatory activities partly by regulating macrophage activation. Therefore, we here investigated the therapeutic potential of TSG-6 in a rat model of CNV induced by laser photocoagulation. Time course analysis showed that the expression of VEGF and pro-inflammatory cytokines in the choroid was up-regulated early after laser injury, and gradually decreased to baseline over 14 days. An intravitreal injection of TSG-6 suppressed the expression of VEGF and pro-inflammatory cytokines including CCL2, and reduced the size of CNV. Also, the number of Iba+ and CCR2+ cells including infiltrating macrophages was markedly lower in the CNV lesion of TSG-6-treated eyes. Further analysis identified CCR2+ CD11b+ CD11c+ cells and CCR2+ CD11b-CD11c+ cells as the cell populations that were increased by laser injury and reduced by TSG-6 treatment. Together, the results demonstrate that TSG-6 inhibits inflammation and CCR2+ monocyte recruitment into the choroid, and suppresses the development of CNV.
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Affiliation(s)
- Sang Jin Kim
- 1] Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Korea [2] Samsung Biomedical Research Institute, 50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Korea
| | - Hyun Ju Lee
- 1] Department of Ophthalmology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea [2] Laboratory of Ocular Regenerative Medicine and Immunology, Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea
| | - Ji-Hyun Yun
- Samsung Biomedical Research Institute, 50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Korea
| | - Jung Hwa Ko
- 1] Department of Ophthalmology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea [2] Laboratory of Ocular Regenerative Medicine and Immunology, Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea
| | - Da Ye Choi
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Korea
| | - Joo Youn Oh
- 1] Department of Ophthalmology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea [2] Laboratory of Ocular Regenerative Medicine and Immunology, Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea
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187
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Vecino E, Rodriguez FD, Ruzafa N, Pereiro X, Sharma SC. Glia-neuron interactions in the mammalian retina. Prog Retin Eye Res 2015; 51:1-40. [PMID: 26113209 DOI: 10.1016/j.preteyeres.2015.06.003] [Citation(s) in RCA: 493] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/18/2015] [Accepted: 06/02/2015] [Indexed: 02/07/2023]
Abstract
The mammalian retina provides an excellent opportunity to study glia-neuron interactions and the interactions of glia with blood vessels. Three main types of glial cells are found in the mammalian retina that serve to maintain retinal homeostasis: astrocytes, Müller cells and resident microglia. Müller cells, astrocytes and microglia not only provide structural support but they are also involved in metabolism, the phagocytosis of neuronal debris, the release of certain transmitters and trophic factors and K(+) uptake. Astrocytes are mostly located in the nerve fibre layer and they accompany the blood vessels in the inner nuclear layer. Indeed, like Müller cells, astrocytic processes cover the blood vessels forming the retinal blood barrier and they fulfil a significant role in ion homeostasis. Among other activities, microglia can be stimulated to fulfil a macrophage function, as well as to interact with other glial cells and neurons by secreting growth factors. This review summarizes the main functional relationships between retinal glial cells and neurons, presenting a general picture of the retina recently modified based on experimental observations. The preferential involvement of the distinct glia cells in terms of the activity in the retina is discussed, for example, while Müller cells may serve as progenitors of retinal neurons, astrocytes and microglia are responsible for synaptic pruning. Since different types of glia participate together in certain activities in the retina, it is imperative to explore the order of redundancy and to explore the heterogeneity among these cells. Recent studies revealed the association of glia cell heterogeneity with specific functions. Finally, the neuroprotective effects of glia on photoreceptors and ganglion cells under normal and adverse conditions will also be explored.
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Affiliation(s)
- Elena Vecino
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - F David Rodriguez
- Department of Biochemistry and Molecular Biology, E-37007, University of Salamanca, Salamanca, Spain
| | - Noelia Ruzafa
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Xandra Pereiro
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Sansar C Sharma
- Department of Ophthalmology, Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA; IKERBASQUE, Basque Foundation for Science at Dept. Cell Biology and Histology, UPV/EHU, Spain
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188
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Li L, Eter N, Heiduschka P. The microglia in healthy and diseased retina. Exp Eye Res 2015; 136:116-30. [PMID: 25952657 DOI: 10.1016/j.exer.2015.04.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 12/25/2022]
Abstract
The microglia are the immune cells of the central nervous system and, also the retina. They fulfil several tasks of surveillance in the healthy retina. In case of an injury or disease, microglia become activated and tries to repair the damage. However, in a lot of cases it does not work, and microglia deteriorate the situation by releasing toxic and pro-inflammatory compounds. Moreover, they further promote degenerative processes by attacking and phagocytosing damaged neurones and photoreceptors that otherwise would possibly have the chance to survive. Such deleterious action of the microglia has been observed in degeneration of retinal ganglion cells and photoreceptors, and it takes place in hereditary diseases, infections as well as in case of traumatic or light injuries. Therefore, a number of attempts has been undertaken so far to inhibit the microglia, with varying success. The task remains to study behaviour of the microglia and their interaction with other retinal cell populations in more detail with respect to released factors and expressed receptors including the time points of the corresponding events. The goal has to be to find a better balance between helpful and detrimental actions of the microglia.
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Affiliation(s)
- Lu Li
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany
| | - Nicole Eter
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany
| | - Peter Heiduschka
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany.
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189
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Franklin TC, Wohleb ES, Duman RS. The Role of Immune Cells in the Brain during Physiological and Pathological Conditions. Psychiatr Ann 2015. [DOI: 10.3928/00485713-20150501-05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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190
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Kern JK, Geier DA, King PG, Sykes LK, Mehta JA, Geier MR. Shared Brain Connectivity Issues, Symptoms, and Comorbidities in Autism Spectrum Disorder, Attention Deficit/Hyperactivity Disorder, and Tourette Syndrome. Brain Connect 2015; 5:321-35. [PMID: 25602622 DOI: 10.1089/brain.2014.0324] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The prevalence of neurodevelopmental disorders, including autism spectrum disorder (ASD), attention deficit/hyperactivity disorder (ADHD), and Tourette syndrome (TS), has increased over the past two decades. Currently, about one in six children in the United States is diagnosed as having a neurodevelopmental disorder. Evidence suggests that ASD, ADHD, and TS have similar neuropathology, which includes long-range underconnectivity and short-range overconnectivity. They also share similar symptomatology with considerable overlap in their core and associated symptoms and a frequent overlap in their comorbid conditions. Consequently, it is apparent that ASD, ADHD, and TS diagnoses belong to a broader spectrum of neurodevelopmental illness. Biologically, long-range underconnectivity and short-range overconnectivity are plausibly related to neuronal insult (e.g., neurotoxicity, neuroinflammation, excitotoxicity, sustained microglial activation, proinflammatory cytokines, toxic exposure, and oxidative stress). Therefore, these disorders may a share a similar etiology. The main purpose of this review is to critically examine the evidence that ASD, ADHD, and TS belong to a broader spectrum of neurodevelopmental illness, an abnormal connectivity spectrum disorder, which results from neural long-range underconnectivity and short-range overconnectivity. The review also discusses the possible reasons for these neuropathological connectivity findings. In addition, this review examines the role and issue of axonal injury and regeneration in order to better understand the neuropathophysiological interplay between short- and long-range axons in connectivity issues.
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Affiliation(s)
- Janet K Kern
- 1 Institute of Chronic Illnesses, Inc. , Silver Spring, Maryland
| | - David A Geier
- 1 Institute of Chronic Illnesses, Inc. , Silver Spring, Maryland
| | | | | | - Jyutika A Mehta
- 3 Communication Sciences & Disorders, Texas Woman's University , Denton, Texas
| | - Mark R Geier
- 1 Institute of Chronic Illnesses, Inc. , Silver Spring, Maryland
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191
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CCR2 antagonism alters brain macrophage polarization and ameliorates cognitive dysfunction induced by traumatic brain injury. J Neurosci 2015; 35:748-60. [PMID: 25589768 DOI: 10.1523/jneurosci.2405-14.2015] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Traumatic brain injury (TBI) is a major risk factor for the development of multiple neurodegenerative diseases. With respect to the increasing prevalence of TBI, new therapeutic strategies are urgently needed that will prevent secondary damage to primarily unaffected tissue. Consistently, neuroinflammation has been implicated as a key mediator of secondary damage following the initial mechanical insult. Following injury, there is uncertainty regarding the role that accumulating CCR2(+) macrophages play in the injury-induced neuroinflammatory sequelae and cognitive dysfunction. Using CX3CR1(GFP/+)CCR2(RFP/+) reporter mice, we show that TBI initiated a temporally restricted accumulation of peripherally derived CCR2(+) macrophages, which were concentrated in the hippocampal formation, a region necessary for learning and memory. Multivariate analysis delineated CCR2(+) macrophages' neuroinflammatory response while identifying a novel therapeutic treatment window. As a proof of concept, targeting CCR2(+) macrophages with CCX872, a novel Phase I CCR2 selective antagonist, significantly reduced TBI-induced inflammatory macrophage accumulation. Concomitantly, there was a significant reduction in multiple proinflammatory and neurotoxic mediators with this treatment paradigm. Importantly, CCR2 antagonism resulted in a sparing of TBI-induced hippocampal-dependent cognitive dysfunction and reduced proinflammatory activation profile 1 month after injury. Thus, therapeutically targeting the CCR2(+) subset of monocytes/macrophages may provide a new avenue of clinical intervention following TBI.
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192
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Kocur M, Schneider R, Pulm AK, Bauer J, Kropp S, Gliem M, Ingwersen J, Goebels N, Alferink J, Prozorovski T, Aktas O, Scheu S. IFNβ secreted by microglia mediates clearance of myelin debris in CNS autoimmunity. Acta Neuropathol Commun 2015; 3:20. [PMID: 25853624 PMCID: PMC4383054 DOI: 10.1186/s40478-015-0192-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/03/2015] [Indexed: 02/07/2023] Open
Abstract
Introduction Multiple sclerosis (MS) is a chronic demyelinating disorder of the central nervous system (CNS) leading to progressive neurological disability. Interferon β (IFNβ) represents a standard treatment for relapsing-remitting MS and exogenous administration of IFNβ exhibits protective effects in experimentally induced CNS autoimmunity. Also, genetic deletion of IFNβ in mice leads to an aggravation of disease symptoms in the MS model of experimental autoimmune encephalomyelitis (EAE). However, neither the underlying mechanisms mediating the beneficial effects nor the cellular source of IFNβ have been fully elucidated. Results In this report, a subpopulation of activated microglia was identified as the major producers of IFNβ in the CNS at the peak of EAE using an IFNβ-fluorescence reporter mouse model. These IFNβ expressing microglia specifically localized to active CNS lesions and were associated with myelin debris in demyelinated cerebellar organotypic slice cultures (OSCs). In response to IFNβ microglia showed an enhanced capacity to phagocytose myelin in vitro and up-regulated the expression of phagocytosis-associated genes. IFNβ treatment was further sufficient to stimulate association of microglia with myelin debris in OSCs. Moreover, IFNβ-producing microglia mediated an enhanced removal of myelin debris when co-transplanted onto demyelinated OSCs as compared to IFNβ non-producing microglia. Conclusions These data identify activated microglia as the major producers of protective IFNβ at the peak of EAE and as orchestrators of IFNβ-induced clearance of myelin debris. Electronic supplementary material The online version of this article (doi:10.1186/s40478-015-0192-4) contains supplementary material, which is available to authorized users.
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193
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Pagani F, Paolicelli RC, Murana E, Cortese B, Di Angelantonio S, Zurolo E, Guiducci E, Ferreira TA, Garofalo S, Catalano M, D'Alessandro G, Porzia A, Peruzzi G, Mainiero F, Limatola C, Gross CT, Ragozzino D. Defective microglial development in the hippocampus of Cx3cr1 deficient mice. Front Cell Neurosci 2015; 9:111. [PMID: 25873863 PMCID: PMC4379915 DOI: 10.3389/fncel.2015.00111] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/11/2015] [Indexed: 11/13/2022] Open
Abstract
Microglial cells participate in brain development and influence neuronal loss and synaptic maturation. Fractalkine is an important neuronal chemokine whose expression increases during development and that can influence microglia function via the fractalkine receptor, CX3CR1. Mice lacking Cx3cr1 show a variety of neuronal defects thought to be the result of deficient microglia function. Activation of CX3CR1 is important for the proper migration of microglia to sites of injury and into the brain during development. However, little is known about how fractalkine modulates microglial properties during development. Here we examined microglial morphology, response to ATP, and K+ current properties in acute brain slices from Cx3cr1 knockout mice across postnatal hippocampal development. We found that fractalkine signaling is necessary for the development of several morphological and physiological features of microglia. Specifically, we found that the occurrence of an outward rectifying K+ current, typical of activated microglia, that peaked during the second and third postnatal week, was reduced in Cx3cr1 knockout mice. Fractalkine signaling also influenced microglial morphology and ability to extend processes in response to ATP following its focal application to the slice. Our results reveal the developmental profile of several morphological and physiological properties of microglia and demonstrate that these processes are modulated by fractalkine signaling.
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Affiliation(s)
- Francesca Pagani
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy
| | - Rosa C Paolicelli
- Division of Psychiatry Research, University of Zürich, Zürich Switzerland ; Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Emanuele Murana
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Barbara Cortese
- Consiglio Nazionale delle Ricerche - Institute of Inorganic Methodologies and Plasmas, Department of Physics, Sapienza University of Rome, Rome Italy
| | - Silvia Di Angelantonio
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy ; Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Emanuele Zurolo
- Department of Neuropathology, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Eva Guiducci
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Tiago A Ferreira
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Stefano Garofalo
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Myriam Catalano
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Giuseppina D'Alessandro
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Alessandra Porzia
- Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome Rome, Italy
| | - Giovanna Peruzzi
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy
| | - Fabrizio Mainiero
- Department of Experimental Medicine, Sapienza University of Rome Rome, Italy
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Cornelius T Gross
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
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194
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Burguillos MA, Svensson M, Schulte T, Boza-Serrano A, Garcia-Quintanilla A, Kavanagh E, Santiago M, Viceconte N, Oliva-Martin MJ, Osman AM, Salomonsson E, Amar L, Persson A, Blomgren K, Achour A, Englund E, Leffler H, Venero JL, Joseph B, Deierborg T. Microglia-Secreted Galectin-3 Acts as a Toll-like Receptor 4 Ligand and Contributes to Microglial Activation. Cell Rep 2015; 10:1626-1638. [PMID: 25753426 DOI: 10.1016/j.celrep.2015.02.012] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 01/23/2015] [Accepted: 02/01/2015] [Indexed: 12/14/2022] Open
Abstract
Inflammatory response induced by microglia plays a critical role in the demise of neuronal populations in neuroinflammatory diseases. Although the role of toll-like receptor 4 (TLR4) in microglia's inflammatory response is fully acknowledged, little is known about endogenous ligands that trigger TLR4 activation. Here, we report that galectin-3 (Gal3) released by microglia acts as an endogenous paracrine TLR4 ligand. Gal3-TLR4 interaction was further confirmed in a murine neuroinflammatory model (intranigral lipopolysaccharide [LPS] injection) and in human stroke subjects. Depletion of Gal3 exerted neuroprotective and anti-inflammatory effects following global brain ischemia and in the neuroinflammatory LPS model. These results suggest that Gal3-dependent-TLR4 activation could contribute to sustained microglia activation, prolonging the inflammatory response in the brain.
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Affiliation(s)
- Miguel Angel Burguillos
- Department of Oncology-Pathology, Cancer Centrum Karolinska, R8:03, Karolinska Institutet, Stockholm 171 76, Sweden; Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, BMC B11, Lund 221 84, Sweden.
| | - Martina Svensson
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, BMC B11, Lund 221 84, Sweden
| | - Tim Schulte
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institutet, Stockholm 17165, Sweden
| | - Antonio Boza-Serrano
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, BMC B11, Lund 221 84, Sweden
| | - Albert Garcia-Quintanilla
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41012, Spain
| | - Edel Kavanagh
- Department of Oncology-Pathology, Cancer Centrum Karolinska, R8:03, Karolinska Institutet, Stockholm 171 76, Sweden
| | - Martiniano Santiago
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41012, Spain
| | - Nikenza Viceconte
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41012, Spain
| | - Maria Jose Oliva-Martin
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41012, Spain
| | - Ahmed Mohamed Osman
- Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Q2:07, Stockholm 171 76, Sweden
| | - Emma Salomonsson
- Section MIG, Department of Laboratory Medicine, Solvegatan 23, Lund University, Lund 223 62, Sweden
| | - Lahouari Amar
- Neuronal Survival Unit, Department of Experimental Medical Science, Wallenberg Neuroscience Center, Lund University, Lund 221 84, Sweden
| | - Annette Persson
- Department of Pathology, Division of Neuropathology, Lund University Hospital, Lund 221 85, Sweden
| | - Klas Blomgren
- Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Q2:07, Stockholm 171 76, Sweden
| | - Adnane Achour
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institutet, Stockholm 17165, Sweden
| | - Elisabet Englund
- Department of Pathology, Division of Neuropathology, Lund University Hospital, Lund 221 85, Sweden
| | - Hakon Leffler
- Section MIG, Department of Laboratory Medicine, Solvegatan 23, Lund University, Lund 223 62, Sweden
| | - Jose Luis Venero
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41012, Spain
| | - Bertrand Joseph
- Department of Oncology-Pathology, Cancer Centrum Karolinska, R8:03, Karolinska Institutet, Stockholm 171 76, Sweden
| | - Tomas Deierborg
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, BMC B11, Lund 221 84, Sweden
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Activation status of human microglia is dependent on lesion formation stage and remyelination in multiple sclerosis. J Neuropathol Exp Neurol 2015; 74:48-63. [PMID: 25470347 DOI: 10.1097/nen.0000000000000149] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Similar to macrophages, microglia adopt diverse activation states and contribute to repair and tissue damage in multiple sclerosis. Using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, we show that in vitro M1-polarized (proinflammatory) human adult microglia express the distinctive markers CD74, CD40, CD86, and CCR7, whereas M2 (anti-inflammatory) microglia express mannose receptor and the anti-inflammatory cytokine CCL22. The expression of these markers was assessed in clusters of activated microglia in normal-appearing white matter (preactive lesions) and areas of remyelination, representing reparative multiple sclerosis lesions. We show that activated microglia in preactive and remyelinating lesions express CD74, CD40, CD86, and the M2 markers CCL22 and CD209, but not mannose receptor. To examine whether this intermediate microglia profile is static or dynamic and thus susceptible to changes in the microenvironment, we polarized microglia into M1 or M2 phenotype in vitro and then subsequently treated them with the opposing polarization regimen. These studies revealed that expression of CD40, CXCL10, and mannose receptor is dynamic and that microglia, like macrophages, can switch between M1 and M2 phenotypic profiles. Taken together, our data define the differential activation states of microglia during lesion development in multiple sclerosis-affected CNS tissues and underscore the plasticity of human adult microglia in vitro.
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196
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Periostin secreted by glioblastoma stem cells recruits M2 tumour-associated macrophages and promotes malignant growth. Nat Cell Biol 2015; 17:170-82. [PMID: 25580734 PMCID: PMC4312504 DOI: 10.1038/ncb3090] [Citation(s) in RCA: 637] [Impact Index Per Article: 70.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 11/26/2014] [Indexed: 02/06/2023]
Abstract
Tumor-associated macrophages (TAMs) are enriched in glioblastoma (GBM) that contains glioma stem cells (GSCs) at the apex of its cellular hierarchy. The correlation between TAM density and glioma grade suggests a supportive role of TAMs in tumor progression. Here we interrogated the molecular link between GSCs and TAM recruitment in GBMs and demonstrated that GSCs secrete Periostin (POSTN) to recruit TAMs. TAM density correlates with POSTN levels in human GBMs. Silencing POSTN in GSCs markedly reduced TAM density, inhibited tumor growth, and increased survival of mice bearing GSC-derived xenografts. We found that TAMs in GBMs are not brain-resident microglia, but mainly monocyte-derived macrophages from peripheral blood. Disrupting POSTN specifically attenuated the tumor supportive M2 type of TAMs in xenografts. POSTN recruits TAMs through integrin αvβ3 as blocking this signaling by an RGD peptide inhibited TAM recruitment. Our findings highlight the possibility of improving GBM treatment by targeting POSTN-mediated TAM recruitment.
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Ceredig RA, Massotte D. Fluorescent knock-in mice to decipher the physiopathological role of G protein-coupled receptors. Front Pharmacol 2015; 5:289. [PMID: 25610398 PMCID: PMC4284998 DOI: 10.3389/fphar.2014.00289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 12/12/2014] [Indexed: 12/21/2022] Open
Abstract
G protein-coupled receptors (GPCRs) modulate most physiological functions but are also critically involved in numerous pathological states. Approximately a third of marketed drugs target GPCRs, which places this family of receptors in the main arena of pharmacological pre-clinical and clinical research. The complexity of GPCR function demands comprehensive appraisal in native environment to collect in-depth knowledge of receptor physiopathological roles and assess the potential of therapeutic molecules. Identifying neurons expressing endogenous GPCRs is therefore essential to locate them within functional circuits whereas GPCR visualization with subcellular resolution is required to get insight into agonist-induced trafficking. Both remain frequently poorly investigated because direct visualization of endogenous receptors is often hampered by the lack of appropriate tools. Also, monitoring intracellular trafficking requires real-time visualization to gather in-depth knowledge. In this context, knock-in mice expressing a fluorescent protein or a fluorescent version of a GPCR under the control of the endogenous promoter not only help to decipher neuroanatomical circuits but also enable real-time monitoring with subcellular resolution thus providing invaluable information on their trafficking in response to a physiological or a pharmacological challenge. This review will present the animal models and discuss their contribution to the understanding of the physiopathological role of GPCRs. We will also address the drawbacks associated with this methodological approach and browse future directions.
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Affiliation(s)
- Rhian A Ceredig
- CNRS, Institut des Neurosciences Cellulaires et Intégratives, UPR 3212 Strasbourg, France
| | - Dominique Massotte
- CNRS, Institut des Neurosciences Cellulaires et Intégratives, UPR 3212 Strasbourg, France
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198
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Wang X, Cao K, Sun X, Chen Y, Duan Z, Sun L, Guo L, Bai P, Sun D, Fan J, He X, Young W, Ren Y. Macrophages in spinal cord injury: phenotypic and functional change from exposure to myelin debris. Glia 2014; 63:635-51. [PMID: 25452166 DOI: 10.1002/glia.22774] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 11/05/2014] [Accepted: 11/12/2014] [Indexed: 01/14/2023]
Abstract
Macrophage activation and persistent inflammation contribute to the pathological process of spinal cord injury (SCI). It was reported that M2 macrophages were induced at 3-7 days after SCI but M2 markers were reduced or eliminated after 1 week. By contrast, M1 macrophage response is rapidly induced and then maintained at injured spinal cord. However, factors that modulate macrophage phenotype and function are poorly understood. We developed a model to distinguish bone-marrow derived macrophages (BMDMs) from residential microglia and explored how BMDMs change their phenotype and functions in response to the lesion-related factors in injured spinal cord. Infiltrating BMDMs expressing higher Mac-2 and lower CX3CR1 migrate to the epicenter of injury, while microglia expressing lower Mac-2 but higher CX3CR1 distribute to the edges of lesion. Myelin debris at the lesion site switches BMDMs from M2 phenotype towards M1-like phenotype. Myelin debris activates ATP-binding cassette transporter A1 (ABCA1) for cholesterol efflux in response to myelin debris loading in vitro. However, this homeostatic mechanism in injured site is overwhelmed, leading to the development of foamy macrophages and lipid plaque in the lesion site. The persistence of these cells indicates a pro-inflammatory environment, associated with enhanced neurotoxicity and impaired wound healing. These foamy macrophages have poor capacity to phagocytose apoptotic neutrophils resulting in uningested neutrophils releasing their toxic contents and further tissue damage. In conclusion, these data demonstrate for the first time that myelin debris generated in injured spinal cord modulates macrophage activation. Lipid accumulation following macrophage phenotype switch contributes to SCI pathology.
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Affiliation(s)
- Xi Wang
- W. M. Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey, New Jersey; Institute of Neurosciences, the Fourth Military Medical University, Xian, China
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199
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IKKβ deficiency in myeloid cells ameliorates Alzheimer's disease-related symptoms and pathology. J Neurosci 2014; 34:12982-99. [PMID: 25253847 DOI: 10.1523/jneurosci.1348-14.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by extracellular amyloid-β (Aβ) deposits and microglia-dominated inflammatory activation. Innate immune signaling controls microglial inflammatory activities and Aβ clearance. However, studies examining innate immunity in Aβ pathology and neuronal degeneration have produced conflicting results. In this study, we investigated the pathogenic role of innate immunity in AD by ablating a key signaling molecule, IKKβ, specifically in the myeloid cells of TgCRND8 APP-transgenic mice. Deficiency of IKKβ in myeloid cells, especially microglia, simultaneously reduced inflammatory activation and Aβ load in the brain and these effects were associated with reduction of cognitive deficits and preservation of synaptic structure proteins. IKKβ deficiency enhanced microglial recruitment to Aβ deposits and facilitated Aβ internalization, perhaps by inhibiting TGF-β-SMAD2/3 signaling, but did not affect Aβ production and efflux. Therefore, inhibition of IKKβ signaling in myeloid cells improves cognitive functions in AD mice by reducing inflammatory activation and enhancing Aβ clearance. These results contribute to a better understanding of AD pathogenesis and could offer a new therapeutic option for delaying AD progression.
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200
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Evans TA, Barkauskas DS, Myers JT, Huang AY. Intravital imaging of axonal interactions with microglia and macrophages in a mouse dorsal column crush injury. J Vis Exp 2014:e52228. [PMID: 25489963 PMCID: PMC4275021 DOI: 10.3791/52228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Traumatic spinal cord injury causes an inflammatory reaction involving blood-derived macrophages and central nervous system (CNS)-resident microglia. Intra-vital two-photon microscopy enables the study of macrophages and microglia in the spinal cord lesion in the living animal. This can be performed in adult animals with a traumatic injury to the dorsal column. Here, we describe methods for distinguishing macrophages from microglia in the CNS using an irradiation bone marrow chimera to obtain animals in which only macrophages or microglia are labeled with a genetically encoded green fluorescent protein. We also describe a injury model that crushes the dorsal column of the spinal cord, thereby producing a simple, easily accessible, rectangular lesion that is easily visualized in an animal through a laminectomy. Furthermore, we will outline procedures to sequentially image the animals at the anatomical site of injury for the study of cellular interactions during the first few days to weeks after injury.
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Affiliation(s)
- Teresa A Evans
- Department of Neurosciences, Case Western Reserve University
| | | | - Jay T Myers
- Department of Pediatrics, Case Western Reserve University
| | - Alex Y Huang
- Department of Pediatrics, Case Western Reserve University;
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